1. Field of the Invention
This invention relates, in general, to dental implants and, more specifically, to endodontic dental implants for insertion into the jawbone of a patient through a bore formed in a tooth to stabilize the tooth.
2. Description of the Prior Art
Endodontic implants or stabilizers have been extensively used to stabilize teeth which have been weakened or loosened due to injury or root disease. Such endodontic implants or stabilizers typically come in two forms--a smooth tapered pin or a threaded, self-tapping pin.
The smooth tapered pin is wedged into a bore formed in the tooth and held in place by a dental cement. This type of dental implant, however, has experienced problems relating to a lack of resistance to withdrawal from the tooth, the formation of a complete apical seal at the apex of the tooth and a poor implant-bone relationship.
The threaded, self-tapping implant, such as that disclosed in U.S. Pat. No. 4,103,422, is formed with threads along the length thereof which engage the sides of the bore within the tooth to form a mechanical seal with the tooth which provides greater implant retention. However, such threaded, self-tapping implants are not without their problems. In using such implants, a bore is initially drilled in the tooth which has the same diameter along its entire length. As the implant is threaded into the bore, the threads engage the sides of the bore along its entire length. At the lower portions of the tooth which have narrowing side walls of reduced thickness, the mechanical force exerted by the threads of the implant on the tooth can cause cracking of the tooth. In addition, due to the presence of the threads along the entire length of the implant, it is difficult to ensure that a complete seal is formed at the lower end of the bore at the apex of the tooth. Furthermore, since this type of implant has a constant diameter along its length, if the bore in the tooth is too large, there is no way to adhere the implant to the tooth or ensure an apical seal. This lack of a complete apical seal commonly leads to failure of the implant in securely retaining the tooth in the jawbone of the patient.
Thus, it would be desirable to provide an endodontic implant which overcomes the problems of the previously devised dental implants. It would also be desirable to provide an endodontic implant which enables a complete apical seal to be formed at the apex of the tooth. Finally, it would be desirable to provide an endodontic dental implant which is formed to exert minimal forces at the lower, narrower regions of the tooth so as to prevent cracking of the tooth in this area.